Coming up with a comprehensive history of the music that led up to Jackie Brenston’s “Rocket 88”?widely regarded as the first true rock’n’roll record?is a virtually impossible task, but this compilation makes a damn fine stab at it. Concentrating heavily on the blues but also taking in country and bluegrass, jug bands, vaudeville, gospel and old-style R&B, this boxed set features exemplary sleevenotes, painstaking track remastering, and stunning covers. One hundred tracks including Leadbelly, Sonny Boy Williamson, Alberta Hunter, The Carter Family, Frank Crumit, and Little Richard spread across four CDs?soon to be available individually.